1. Field of the Invention
The present invention relates to an image reproducing apparatus for reading an original image and reproducing the original image onto a recording material.
2. Related Background Art
In a conventional copying apparatus, since there is a limitation on the size of sheet which can be used, there is a case where when an enlargement copy is made, only a part of the original is obtained in the output copy.
Therefore, to avoid the above drawback, the function for automatically dividing an enlargement reproduction image of an original image and outputting the enlargement onto a plurality of sheets has been proposed in U.S. Pat. Nos. 4,853,752, 4,905,095 and 4,947,269. In the following description, such a function is called a multi-page enlargement and its idea will be described in more detail by using FIGS. 13-1 to 13-3.
FIG. 13-1 shows an original, of length DX in the main scan direction and DX in the subscan direction. (Hereinbelow, suffix X indicates the main scan direction and "Y" represents the subscan direction.) FIG. 13-3 shows a final copy output whose size is (I.e., CX by CY). The final copy output is obtained as a result of the original having been enlarged at magnifications of MX and MY. The final output comprises four sheets each having a size of (PX, PY) as shown in, for example, FIG. 13-2 and the respective sheets are adhered so as to overlap by only a length of AX or AY as shown in the diagram, so that the final copy output of FIG. 13-3 is obtained. AX is obtained by AX=2PX-DX.multidot.MX and AY is derived by AY=2PY-DY.multidot.MY.
In the case where the number of sheets is further generally expressed and NX sheets are used in the main scan direction and NY sheets are used in the subscan direction, NX is equal to the minimum integer larger than ##EQU1## and NY is similarly equal to the minimum integer larger than ##EQU2## In this case, ##EQU3## When NX or NY is equal to 1, AX or AY is set to 0.
The above is the idea of the function of the multi-page enlargement mentioned above. As an actual application example, the magnifications MX and MY are set by the operator, the numbers of sheets NX and NY, the overlap widths AX and AY, and the like are automatically calculated from the original size and the sheet size, and the operations are executed.
However, in the above conventional example, if the operator tries to realize the set magnification and output size at a high fidelity, it may occur that the original is divided into a larger number of sheets than expected.
That is, such a situation corresponds to the case where the value of DX.multidot.MX is very slightly larger than (NX-1).multidot.PX or the value of DY.multidot.MY is very slightly larger than (NY-1).multidot.PY.
In such a case, since NX.times.NY is selected as the number of output sheets, the overlap amounts AX and AY are larger than needed, the total number of output sheets is also large, and it is very uneconomical.